A known fingermouse, or finger navigation device operated in a scrolling manner is capacitance based. The capacitance based device generally does not operate satisfactorily if the finger is covered, for example, by a glove. Moreover, the size of the capacitance based device may be large in relation to other devices, such as, a mobile phone, and a personal digital assistant (PDA).
An optical navigation device is also known, which operates on the same principles as optical mice by comparing successive frames of an area image. The optical navigation device tends to be smaller, but there is typically a practical limit on reducing thickness because of the minimum focal length to form an image on the surface of an image sensor.
Thus, it may be desirable to provide a fingermouse navigation device which can be manufactured with a reduced thickness. It is also desirable to manufacture such a device in a relatively simple manner and with a relatively low part count.